I always believed that if someone truly wants to get in your suitcase, they'll just steal the whole thing instead of bothering to go through it where everyone can see. I lock our suitcases when we fly, not because I am afraid that someone will steal something out of it, but to keep the zipper from opening.
I never leave anything valuable in our suitcases. It all goes in our carry on. If it doesn't fit in there, it doesn't go.
I assume you have TSA locks since otherwise it is illegal to lock suitcases on a plane these days.
What is nomal procedure for suitcases when boarding...taking a seperate bag with me full of camera, etc.
There is NOTHING illegal about using any lock on your luggage. TSA locks are the only locks that the TSA officials have master keys too. Other locks can be cut off. TSA rules DO NOT APPLY to cruiselines. You are not required to use a TSA lock on a cruise.